com.hp.hpl.jena.graph.query
Class SimpleQueryHandler

java.lang.Object
  com.hp.hpl.jena.graph.query.SimpleQueryHandler

All Implemented Interfaces:

QueryHandler

public class SimpleQueryHandler

extends java.lang.Object

implements QueryHandler

Constructor Summary

SimpleQueryHandler(Graph graph)
make an instance, remember the graph

Method Summary

boolean	containsNode(Node n) this is a simple-minded implementation of containsNode that uses find up to three times to locate the node.
boolean	isEmpty() Answer true iff the subject graph is empty.
ExtendedIterator	objectsFor(Node s, Node p) deliver an iterator over all the objects _o_ such that _(s, p, o)_ is in the underlying graph; nulls count as wildcards.
Stage	patternStage(Mapping map, Graph constraints, Triple[] t) produce a single Stage which will probe the underlying graph for triples matching p and inject all the resulting bindings into the processing stream (see Stage for details) _map_ is the variable binding map to use and update.
BindingQueryPlan	prepareBindings(Query q, Node[] variables) prepare a plan for generating bindings given the query _q_ and the result variables _variables_.
TreeQueryPlan	prepareTree(Graph pattern) deliver a plan for executing the tree-match query defined by _pattern_.
ExtendedIterator	subjectsFor(Node p, Node o) deliver an iterator over all the subjects _s_ such that _(s, p, o)_ is in the underlying graph; nulls count as wildcards.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

SimpleQueryHandler

public SimpleQueryHandler(Graph graph)

make an instance, remember the graph

Method Detail

patternStage

public Stage patternStage(Mapping map,
                          Graph constraints,
                          Triple[] t)

Description copied from interface: QueryHandler

produce a single Stage which will probe the underlying graph for triples matching p and inject all the resulting bindings into the processing stream (see Stage for details)
_map_ is the variable binding map to use and update. _constraints_ is the current constraint graph: if this Stage can absorb some of the constraints, it may do so, remove them from the graph.

Specified by:

patternStage in interface QueryHandler

prepareBindings

public BindingQueryPlan prepareBindings(Query q,
                                        Node[] variables)

Description copied from interface: QueryHandler

prepare a plan for generating bindings given the query _q_ and the result variables _variables_.

Specified by:

prepareBindings in interface QueryHandler

prepareTree

public TreeQueryPlan prepareTree(Graph pattern)

Description copied from interface: QueryHandler

deliver a plan for executing the tree-match query defined by _pattern_.

Specified by:

prepareTree in interface QueryHandler

objectsFor

public ExtendedIterator objectsFor(Node s,
                                   Node p)

Description copied from interface: QueryHandler

deliver an iterator over all the objects _o_ such that _(s, p, o)_ is in the underlying graph; nulls count as wildcards.

Specified by:

objectsFor in interface QueryHandler

subjectsFor

public ExtendedIterator subjectsFor(Node p,
                                    Node o)

Description copied from interface: QueryHandler

deliver an iterator over all the subjects _s_ such that _(s, p, o)_ is in the underlying graph; nulls count as wildcards.

Specified by:

subjectsFor in interface QueryHandler

containsNode

public boolean containsNode(Node n)

this is a simple-minded implementation of containsNode that uses find up to three times to locate the node. Almost certainly particular graphs will be able to offer better query-handlers ...

Specified by:

containsNode in interface QueryHandler

isEmpty

public boolean isEmpty()

Answer true iff the subject graph is empty.

Specified by:

isEmpty in interface QueryHandler